Ionospheric irregularities produced by internal atmospheric gravity waves

Hooke, William H.

doi:10.1029/gm018p0780

Cited by 101 publications

(174 citation statements)

References 25 publications

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“…The ions are magnetized and, in presence of an AGW, can only move along the magnetic field lines with a velocity equal to the component of the neutral gas velocity parallel to the Earth's magnetic field. Hooke [1968] has analyzed the temporal and spatial variations of the plasma density and ion velocity in TIDs in the altitude range where ion and neutrals are effectively coupled by collisions. For a neutral density n N $ 10 15 m À3 , an ion density n i $ 10 11 m À3 and temperature T $ 1000 K at the peak of the F-layer near 300 km, the ion-neutral collision frequency is $1.0 Hz.…”

Section: Discussionmentioning

confidence: 99%

First simultaneous observations of daytime MSTIDs over North America using GPS‐TEC and DEMETER satellite data

Onishi¹,

Tsugawa²,

Otsuka³

et al. 2009

Geophysical Research Letters

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[1] We present simultaneous observations of daytime medium-scale traveling ionospheric disturbances (MSTIDs) over North America, using measurements of the Total Electron Content (TEC) by the US GPS network and ionospheric plasma data from the DEMETER microsatellite. Several events show latitudinal variations of the plasma parameters at satellite altitude corresponding to the MSTID structures revealed on 2D TEC maps. In a case study with a very well defined MSTID, quasi periodic variations of the plasma density and of the ion velocity parallel to the Earth's magnetic field are observed along the satellite orbit that match the signature of the MSTID on the TEC maps. We believe it is the first simultaneous observation of parallel plasma motion in the topside ionosphere and propagating MSTID structures in the F-region. An initial analysis of this event is performed in the light of results from simple model of ionospheric disturbances associated with Atmospheric Gravity Waves (AGWs).

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Section: Discussionmentioning

confidence: 99%

First simultaneous observations of daytime MSTIDs over North America using GPS‐TEC and DEMETER satellite data

Onishi¹,

Tsugawa²,

Otsuka³

et al. 2009

Geophysical Research Letters

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“…Then The ability of gravity waves to create structure in the ionosphere at midlatitudes has been understood for many years. The classic paper by Hooke [1968] There are some problems with this explanation, however. First, the height is well above the maximum growth rate for such a midlatitude process which is closer to 160 km.…”

Section: Discussionmentioning

confidence: 99%

In situ ionospheric observations of severe weather‐related gravity waves and associated small‐scale plasma structure

Kelley¹

1997

J. Geophys. Res.

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Abstract. On July 27, 1988, two sounding rockets were launched over a small thunderstorm cell which constituted the remnants of a large frontal event which had lasted for several hours over the eastern seaboard. One of the rockets was instrumented for detection of the electromagnetic impulse from lightning strikes and its subsequent interaction with the ionospheric plasma [Kelley et al., 1990]. The second had on board an absolute electron density probe, the results from which we report here. We present evidence that a gravity wave was spawned by the front and propagated nearly to the F peak in the ionosphere, where it steepened and created structure in the medium at scales much less than the vertical wavenumber of the major disturbance. The fluctuation spectrum along the rocket path was elevated for scales from 25 km down to less than 10 m. At scales between 10 km and just under 100 m, characterization of the spectrum by a power law yields a spectral index less than that displayed by such well-studied processes as bottomside spread F and barium cloud striations. Similar results have been reported for gravity wave induced intermediate scale structures at midlatitudes [Wernik et al., 1986]. The mixing theory described by Fridrnan [1990] may be relevant to these observations.

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“…Following his pioneer work, the ®eld-aligned ionneutral interaction along with the e ects of the ambipolar di usion were formulated theoretically by Hooke (1968) and Testud and Francois (1971). Experimental evidence that agrees with previous theories has been reported, it was based on observations of neutral oscillations with all-sky imagers, photometers, and mass spectrometers on board satellites (e.g.…”

Section: Introductionmentioning

confidence: 91%

Effects of atmospheric oscillations on the field-aligned ion motions in the polar F-region

Oyama¹,

Nozawa²,

Buchert³

et al. 2000

Ann. Geophys.

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Abstract. The ®eld-aligned neutral oscillations in the F-region (altitudes between 165 and 275 km) were compared using data obtained simultaneously with two independent instruments: the European Incoherent Scatter (EISCAT) UHF radar and a scanning FabryPerot interferometer (FPI). During the night of February 8, 1997, simultaneous observations with these instruments were conducted at Troms , Norway. Theoretically, the ®eld-aligned neutral wind velocity can be obtained from the ®eld-aligned ion velocity and by di usion and ambipolar di usion velocities. We thus derived ®eld-aligned neutral wind velocities from the plasma velocities in EISCAT radar data. They were compared with those observed with the FPI (k 630:0 nm), which are assumed to be weighted height averages of the actual neutral wind. The weighting function is the normalized height dependent emission rate. We used two model weighting functions to derive the neutral wind from EISCAT data. One was that the neutral wind velocity observed with the FPI is velocity integrated over the entire emission layer and multiplied by the theoretical normalized emission rate. The other was that the neutral wind velocity observed with the FPI corresponds to the velocity only around an altitude where the emission rate has a peak. Di erences between the two methods were identi®ed, but not completely clari®ed. However, the neutral wind velocities from both instruments had peak-to-peak correspondences at oscillation periods of about 10±40 min, shorter than that for the momentum transfer from ions to neutrals, but longer than from neutrals to ions. The synchronizing motions in the neutral wind velocities suggest that the momentum transfer from neutrals to ions was thought to be dominant for the observed ®eld-aligned oscillations rather than the transfer from ions to neutrals. It is concluded that during the observation, the plasma oscillations observed with the EISCAT radar at di erent altitudes in the F-region are thought to be due to the motion of neutrals.

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Ionospheric irregularities produced by internal atmospheric gravity waves

Cited by 101 publications

References 25 publications

First simultaneous observations of daytime MSTIDs over North America using GPS‐TEC and DEMETER satellite data

First simultaneous observations of daytime MSTIDs over North America using GPS‐TEC and DEMETER satellite data

In situ ionospheric observations of severe weather‐related gravity waves and associated small‐scale plasma structure

Effects of atmospheric oscillations on the field-aligned ion motions in the polar F-region

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